In today's energy conservation conscious world, finding ways to better insulate our homes, is foremost on the minds of a great many people. Many different materials have been used for such insulation. For example, fiberglass insulation provides good insulation characteristics for insulation of walls, ceilings, etc. of homes. However, this type of insulation is not capable of insulating narrow hollow cavities within window lineals which are prevalently used in replacement vinyl windows.
Present commercial methods of filling channels of an extruded lineal with liquid foamable resin result in substantial voids throughout the length of the channel, reducing the advantages of filling the channel with foam. In one method, a foam application gun is equipped with a metal tubular extension of three feet or longer. The extension is inserted into one open end of the lineal channel and liquid foamable polyurethane foam is then dispensed into the channel. The channel is moved away from the gun to fill one-half of the channel and the process repeated from the opposite end. In another method, a polyurethane pour gun is fitted with a flexible hose which is inserted several feet into the lineal channel. The hose is then withdrawn as the liquid polyurethane foam is poured into the lineal channel, allowing the filling of the lineal channel from one end. The rate of withdrawal of the hose must be accurately controlled and one operator generally withdraws the hose as the second operator operates the pour gun. However, either method typically results in substantial voids throughout the lineal channel or inconsistent filling.
Another method is to fill elongated channels by directing a stream of liquid foamable polymeric resin into the channel from one end. The lineal is first oriented at an angle generally of about 60° and the application gun is then operated to direct a thin elongated stream of foamable polyurethane into the lineal from the top open end, preferably coincident with the longitudinal axis of the channel, such that the stream impinges at or near the bottom of the channel and the foam rises upwardly through the channel and fills the channel. It is believed that at least one problem with this approach is that the application gun covers the open end of the channel such that the operator cannot accurately align the stream of liquid foamable resin into the channel. If the nozzle of the application gun is not accurately aligned with the longitudinal axis of the channel, the stream will impinge the side wall of the channel creating a backflowing/expanding foam that in turn, blocks the stream and prevents complete filling of the channel. This is a problem in mass production applications in that the channels are relatively small in cross-section and the length of the channel is generally twelve or sixteen feet in length.
Therefore, it is easily seen that what is needed is a way to dispense foam into elongated hollow cavities in which there is minimal to no damage to the original cross-sectional dimensions of the profile, regardless of whether that deformation is attributable to heat or pressure due to foam expansion or combinations thereof.